Lang Tools TU-32-21 Compucheck Fuel System Restriction Test Gauge Check fuel system restriction on diesel engines with a Compuchek test port Fits Compuchek test ports on Cummins, International and Detroit Diesel engines as well as other diesel engines that have been outfitted with the Compuchek test port Consists of a hose assembly with a female Compuchek fitting on one end and a 3-1/2", 30 inHg vacuum gauge on the other